I'm similar to Randomnity in that I'm more likely to just let the friendship fade into nothingness. But I've never really been in the situation where someone has treated me badly enough for me to completely cut contact with them. I'm the sort of person who can stay friends with their ex as well (if I had one).
Part of me thinks the whole INFJ doorslamming business might be more noticeable due the formalness of it all. There's also the whole sensitivity thing in play where INFJs, to me, can come across as more tough-minded and decisive with the "This is making me uncomfortable. I'm not going to take this anymore." approach than say an ISFJ who might end up staying in an uncomfortable environment for way too long. Granted, this is not to say that the INFJ hurts less from the whole ordeal.
When the cutting off happens, rather than it being explosive, it's much more likely to be formal and to the point which can come across as extremely cold. I'd imagine the stark difference between how close the person used to be, and how formal and distant they will become when door-slamming basically creates a massive impression in people's mind. It actually makes the whole cutting off business potentially more painful (as if they suddenly switched off all feelings) than if you had witnessed a person explode with high amount of emotions and so fourth.
That's my take on it anyway. I think all people probably doorslam, but I think the whole formality aspect of it might be more unique to people who control their emotions (An Fe thing?) that is often observed in INFJs. My INFJ friend for the most part has cut me out of her life (It was semi-romantic at one point), and I can feel it. We're just on cordial terms these days. It's a little unfortunate really.